Landing indicator for logging tools

ABSTRACT

An apparatus for evaluating an earth formation intersected by a wellbore may include a logging tool conveyed into the wellbore through a drilling tubular, a landing indicator associated with the logging tool, and a sensor operatively associated with the logging tool. In use, the landing indicator generates a pressure pulse in the drilling tubular after contacting a travel restrictor positioned in the drilling tubular. After the logging tool is positioned at the target depth, the sensor makes at least one measurement while the logging tool is in the drilling tubular and provides an output indicative of a selected subsurface parameter.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

This disclosure relates generally to logging a well during tripping of adrill string.

2. Background of the Art

Oil or gas wells are often logged to determine one or more geological,petrophysical, geophysical, and well production properties (“parametersof interest”) using electronic measuring instruments conveyed along awellbore. Tools adapted to perform such surveys are sometimes referredto as logging tools. These tools may use electrical, acoustical, nuclearand/or magnetic energy to investigate a formation traversed by thewellbore. Well logging can be performed at various stages of wellconstruction. In some aspects, the present disclosure relates to loggingtools that may be used while a drill string is tripped out of thewellbore.

SUMMARY OF THE DISCLOSURE

In aspects, the present disclosure provides an apparatus for use in awellbore. The apparatus may include a tool conveyed into the wellborethrough a drilling tubular, a landing indicator associated with the toolthat generates a pressure pulse in the drilling tubular after contactinga travel restrictor positioned in the drilling tubular, and a sensorassociated with the tool that estimates at least one selected subsurfaceparameter while the tool is in the drilling tubular.

In aspects, the present disclosure provides a method of using a tool ina wellbore. The method may include estimating at least one subsurfaceparameter using a sensor associated with a tool after receiving apressure pulse generated by a landing indicator associated with thetool, wherein the landing indicator generates the pressure pulse inresponse to contact with a travel restrictor in the drilling tubular.

In aspects, the present disclosure further provides an apparatus for usein a wellbore. The tool may be configured to be conveyed into thewellbore and have a landing indicator that generates a pressure pulse ina fluid column in the wellbore after contacting a travel restrictorpositioned in the wellbore.

Examples of certain features of the disclosure have been summarizedrather broadly in order that the detailed description thereof thatfollows may be better understood and in order that the contributionsthey represent to the art may be appreciated. There are, of course,additional features of the disclosure that will be described hereinafterand which will form the subject of the claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

For a detailed understanding of the present disclosure, reference shouldbe made to the following detailed description of the embodiments, takenin conjunction with the accompanying drawings, in which like elementshave been given like numerals, wherein:

FIG. 1 illustrates a drilling system made in accordance with oneembodiment of the present disclosure;

FIG. 2 schematically illustrates a logging while tripping device made inaccordance with one embodiment of the present disclosure;

FIG. 3 illustrates a landing indicator made in accordance with oneembodiment of the present disclosure; and

FIGS. 4 & 5 illustrate successive stages of activation of the FIG. 3embodiment of a landing indicator.

DETAILED DESCRIPTION OF THE DISCLOSURE

Aspects of the present disclosure provide a landing indicator thatsignal when a logging tool has landed at a target location in awellbore. In some arrangements, the landing indicator is attached to alogging tool and is actuated by contact with a feature that obstructsaxial travel along a bore of a drill string. The travel restrictingfeature may be disposed at a selected location along the bore of a drillstring; e.g., at a bottom end of a drill string. In response to contactwith the travel restricting feature, the landing indicator generates adiscernable short-duration pressure spike in a fluid column inside thedrill string. This pressure spike indicates to personnel that thelogging tool has landed at the target location.

Landing indicators in accordance with the present disclosure may be usedto accurately position a logging tool at a target location inside anumbilical associated with a drilling system adapted to form a wellbore.Referring now to FIG. 1, there is schematically illustrated one suchdrilling system 10 for forming a wellbore 12 in an earthen formation 13.While a land-based rig is shown, these concepts and the methods areequally applicable to offshore drilling systems. Also, the wellbore 12may include vertical sections, deviated sections, and horizontalsections, as well as branch wellbores. The drilling system 10 may use abottomhole assembly (BHA) 14 conveyed by an umbilical such as a drillstring 16 suspended from a rig 18. The drill string 16 may include adrill bit 20 at a distal end. The drill string 16 may be include anyknown drilling tubular adapted for use in a wellbore, e.g., jointeddrill pipe, coiled tubing, casing, liner, etc.

For a variety of reasons, the drill string 16 may be “tripped” out of awellbore. As used herein, the term “trip” or “tripping” refers tomovement of the drill string 16 along the wellbore 12; e.g., “trippingout” refers to extraction of the drill string 16 from a wellbore 12. Forinstance, the drilling may be completed or drill string equipment mayneed repair/replacement. During these situations, an accuratelypositioned logging tool 50, shown in hidden lines, may be used toacquire information relating to the wellbore 12 and/or formation 13while the drill string 16 is tripped out of the wellbore 12.

FIG. 2 illustrates the exemplary components of a logging tool 50 thatmay be used to log a well while the drill string 16 is tripped out ofthe wellbore 12. The logging tool 50 is shown positioned inside aportion of the drill string 16 and at the target location. In theembodiment shown, the logging tool 50 includes a power section 52, acontroller 54 for operating the logging tool 50, and a sensor section 56for logging the well. These components may be inside one unitarystructure, within separate interconnected modules, or otherwiseassociated with the logging tool 50. The power section 52 may includeresident electrical power sources such as batteries to energize thecomponents of the logging tool 50. The controller 54 may includeinformation processing devices such as processors programmed withinstructions and memory modules for storing information acquired duringthe logging activity.

The sensor section 56 includes instruments for estimating parameters ofinterest relating to one or more selected subsurface features such asthe formation 13 and/or the wellbore 12. In some embodiments of thepresent disclosure, the logging tool 50 resides inside of the drillstring 16. Thus, the sensor section 56 may include instruments that canmeasure wellbore or formation properties through a wall of a wellboretubular such as the drill string 16 or casing (not shown), including butlimited to pulsed neutron logging tools, neutron porosity tools usingchemical neutron sources, cased hole resistivity tools, or acoustictools. However, it should be appreciated that the teachings of thepresent disclosure are not limited to any specific types of instruments.Thus, the sensor section 56 may include resistivity tools, nuclearmagnetic resonance (NMR) tools, and other well logging tools thatprovide information relating to a geological parameter, a geophysicalparameter, a petrophysical parameter, and/or a lithological parameter.The sensor section 56 may include sensors that output signalsrepresentative of a sensed parameter and sources (e.g., pulsed neutrons)that emit an energy wave into the formation 13. Other illustrativeinstruments used in the sensor section 56 may estimate dielectricconstant, the presence or absence of hydrocarbons, acoustic porosity,bed boundary, formation density, nuclear porosity and certain rockcharacteristics, permeability, capillary pressure, and relativepermeability. The tools may also estimate wellbore parameters such asinclination, azimuth, wellbore diameter, rugosity, etc. These parameterscollectively will be referred to as “subsurface” parameters.

As is known, the information obtained by the sensor section 56 should becorrelated with depth along the wellbore 12 in order to properlycharacterize the formation. Therefore, it is desirable to position thelogging tool 50 at a reference depth in the wellbore 12 to enable anaccurate correlation between the obtained information and well depth.Thus, the logging tool 50 includes a landing indicator 60 that signalsto the surface that logging tool 50 has reached the reference depth, ortarget depth, in the wellbore 12. In some embodiments, the target depthmay be a location proximate to the drill bit 20 (FIG. 1) or BHA 14 (FIG.1). In general, the target depth may be any known location along thedrill string 16.

In one embodiment, the landing indicator 60 is configured to generate aunique and discernable pressure pulse after the logging tool 50 reachesthe target depth. As will be described below, the landing indicator 60interferingly contacts a travel restrictor 26 that has been fixed at adesired location in the drill string 16. A travel restrictor 26 may beany device that projects radially inwardly into the drill string bore 24and presents one or more surfaces that block passage of all or a portionof the logging tool 50. For example, the travel restrictor 26 may be abaffle plate that is interconnected between two jointed tubulars. Whenactuated by contact with the travel restrictor 26, the landing indicator60 temporarily restricts flow and thereby generates a pressure pulse ina fluid column in the drill string bore 24. Pressure transducers, orother pressure detectors, in communication with the fluid column in thedrill string bore 24 may be used to detect this pressure pulse.

Referring now to FIG. 3, in one embodiment, the landing indicator 60 mayinclude a sliding sleeve 62 that is mounted on a mandrel 64 in atelescopic fashion. The mandrel 64 has an upper section 66 and a lowersection 68. Initially, the sliding sleeve 62 is disposed around theupper section 66 and fixed to the mandrel 64 using frangible elementssuch as shear screws 70. The annular space 72 between the sliding sleeve62 and the upper section 66 is sized to receive a flow dam 74. The uppersection 66 may include a collared end 76 that secure the mandrel 64 to aconnector 78. The connector 78 may be an intermediate sub or otherlinking device that couples the landing indicator 60 to the logging tool50. Of course, the landing indicator 60 may be associated with thelogging tool 50 using other structural arrangements as well. The lowersection 68 includes an engagement head 80 that has a diameter greaterthan an inner diameter of the travel restrictor 26.

The sliding sleeve 62 may be configured to selectively release the flowdam 74 after the landing indicator 60 reaches the target depth. In oneembodiment, the sliding sleeve 62 may be a tubular member having one ormore swab cups 82 affixed to an outer radial surface. The swab cups 82may be flexible ring shaped members that restrict flow in one directionalong an annulus 36 formed between the logging tool 50 and the wall ofthe drill string 16 (FIG. 2). The pressure differential associated withthis flow restriction generates an axial force that is applied to thesliding sleeve 62. When the logging tool 50 is “pumped down” in thewellbore, the swab cups 82 use this axial force to propel the landingindicator 60 through the drill string 16. After the mandrel 64 of thelanding indicator 60 seats on a travel restrictor 26, the swab cups 82use this axial force to shear the shear screws 70 and slide the slidingsleeve 62 toward the lower section 68. Optionally, a temporary lockingelement 71 such as a safety pin may be used to prevent relative movementbetween the sliding sleeve 62 and the mandrel 64 during lifting andhandling at the surface. The locking element 71 is removed before thelogging tool 50 is tripped into the wellbore 12.

When the sliding sleeve 62 encloses the flow dam 74, the device 54 is inthe pre-activated state. When the sliding sleeve 64 slides over thelower section 68 and uncovers the flow dam 74, the landing indicator 60is in the activated state.

When the landing indicator 60 is in the activated state, the flow dam 74generates a pressure pulse in the fluid column in the drill string bore24. In one arrangement, the flow dam 74 may be a pliable umbrella-likeelement that, when closed, nests within the annular space 72. Whenactivated by a specified pressure or flow rate, the flow dam 74 firstunfolds to block or occlude an annular flow space 36 (FIG. 2) betweenthe logging tool 50 and an inner wall of the drill string 24 (FIG. 2).The flow dam 74 may be constructed to maintain structural integrity andresist flow up to a specified value (or collapse value). A fluidpressure or flow rate in excess of the collapse value causes the flowdam 74 to collapse. In one embodiment, the flow dam 74 collapses byinverting, i.e., turning inside out. It should be understood that theflow dam 74 may also collapse by shearing, fragmenting, tearing, orbreaking in a manner that reduces the resistance to fluid flow. Thisreduced resistance causes the pressure in the fluid column to drop. Theradial expansion and radial collapse of the flow dam 74 causes apressure pulse in the drill string bore 24 that travels to the surface.In some embodiments, the flow dam 74 may be formed of a polymer (e.g.,rubber) or other similar material that is sufficiently flexible and candeform (e.g., bend or fold) when subjected to fluid pressure. In someembodiments, the flow dam 74 may be constructed in an umbrella-likefashion having a polymeric webbing that is reinforced by rods.

Referring now to FIGS. 1 and 2, in one illustrative operation, thelogging tool 50 is inserted into the bore 24 of the drill string 16after drilling has stopped. A variety of methods may be used to conveyand position the logging tool 50 at the target depth. In someembodiments, the tool 50 may free fall through the drill string bore 24under the effect of primarily gravity. In other embodiments, the loggingtool 50 may be propelled using hydraulic pressure. For instance, pumps34 at the surface may pump drilling fluid into the bore 24 to propel thelogging tool 50. In still other embodiments, a combination of gravityand hydraulic pressure may be used to move the logging tool 50 to thetarget depth.

Once at the target depth, the logging tool 50 will pass through thevarious discrete stages of activation as shown in FIGS. 3-5. In FIG. 3,the logging tool 50 shown at the target depth and having just madecontact with the travel restrictor 26. Because the travel restrictor 26prevents downward axial movement of the mandrel head 80, the axialloadings induce a shearing stress at the shear screws 70. These axialloadings may be generated by the weight of the logging tool 50 and/orpressurized drilling fluid circulating in the drill string bore 24. At apredetermined value, the shear screws 70 break and release the slidingsleeve 62 from the mandrel 64.

In FIG. 4, the sliding sleeve 62 is shown shifted to the activatedposition. As noted previously, gravity alone may be used to shift thesliding sleeve 66. In that instance, the mud pumps 34 (FIG. 1) may beoperated to pump fluid into the drill string bore 24. If the loggingtool 50 had been “pumped down,” then drilling fluid is already flowingin the drill string bore 24. Once the flow dam 74 is exposed to theflowing fluid, the flow dam 74 unfolds and substantially blocks theannular passage 36 of the drill string bore 24. By substantially, it ismeant that enough fluid flow is blocked to cause a pressure spike(increase) that can be detected the surface. Thus, personnel monitoringthe fluid pressure in the drill string bore 24 will detect an increasein pressure. This pressure reading provides a preliminary indication topersonnel that the logging tool 50 may have reached the target depth.

A definitive indication that the logging tool 50 has landed at thetarget depth may be obtained when the logging tool 50 is in the stateshown in FIG. 5. In FIG. 5, the flow dam 74 has inverted due to thefluid flow in the drill string bore 24 (FIG. 2) exceeding the collapsevalue of the flow dam 74. The webbing of the flow dam 74 is radiallycompressed such that flow along the annulus 36 is no longersubstantially restricted. That is, the flow dam 74 has reduced incross-sectional size sufficient to cause a pressure drop that can bedetected at the surface. Moreover, this pressure drop is of sufficientmagnitude as to be uniquely attributed to the collapse of the flow dam74. The flow dam 74 is shown covering the swab cups 82. However, theswabs 82 can remain exposed in some situations. It should be noted thatthe contact of the mandrel head 80 with the travel restrictor 26 doesnot substantially block fluid flow along the drill string bore 24. Thatis, the travel restrictor 26 may have slots, channels, or other flowpassages that allow fluids to flow between the travel restrictor 26 andthe mandrel head 80. Thus, fluid circulation may remain substantiallythe same in the period before and the period after the activation of thelanding indicator 60. During activation, the fluid circulation isaffected by the pressure pulse as described above.

The combination of a pressure increase due to activation of the flow dam74 as shown in FIG. 4 and the subsequent pressure drop due to thecollapse of the flow dam 74 as shown in FIG. 5 generate a pressuresignal that indicates to personnel that the logging tool 50 has landedat the target depth. A variety of flow regimes may be used to expand andcollapse the flow dam 74. For instance, the mud pump 34 (FIG. 1) mayinitiate fluid flow in the drill string bore 24 with a sufficient flowrate/pressure to expand and collapse the flow dam 74. In another regime,the pump 34 may initiate fluid flow with sufficient flow rate/pressureto only expand the flow dam 74. Once a pressure increase is detected,the mud pump 34 (FIG. 1) may be adjusted to increase the flowrate/pressure to collapse the flow dam 74.

Referring now to FIG. 1, the drill string 16 may now be tripped out ofthe wellbore 12. As the logging tool 50 travels uphole, onboard sensorsand related equipment log the well using instruments discussedpreviously, e.g., gamma ray tools, pulsed neutron tools, etc. As notedpreviously, the logging tool 50 may be positioned inside the drillstring 16. Therefore, the instruments in the sensor section 56 areconfigured to use techniques that are not impaired by an interveningbarrier such as a metal tubular wall. Also, in these embodiments, thelogging tool 50 is an “autonomous” tool in that the logging tool 50 isenergized and operated using on-board devices and components. Afterbeing recovered at the surface, the memory modules of the logging tool50 are accessed to retrieve the logging information. It should beappreciated that the information obtained by the logging tool 50 can beaccurately correlated with the depth along the wellbore 12 because thetarget depth, which is the depth at which logging started, had beenaffirmatively established using the landing indicator 60.

It should be understood that the logging tool 50 is susceptible tovarious modifications and variations. For instance, the travelrestrictor 26 may allow axial passage of the mandrel 64 but blockpassage of the sliding sleeve 62. In that arrangement, the impact of thesliding sleeve 62 against the travel restrictor 26 shears the shearscrews 70 and allows the mandrel 64 and flow dam 74 to continue to slidedownward. The exposed flow dam 74 then inflates and inverts aspreviously described. As described previously, one or several methodsmay be used to shift the sliding sleeve 62. For vertical or deviatedwells, gravity may be used to generate an impact force that shifts thesliding sleeve 62. In horizontal wells, the swab cups 82 may beconfigured to provide enough restriction to provide a significant axialforce on the sliding sleeve 62 to break shear screws 70 and slide touncover the flow dam 74, which inflates and then inverts to generate thepressure signal. In another version,

In the arrangements described above, the logging tool 50 is constructedto function as a “drop tool” (e.g., a ‘go devil’). A “drop tool” is adevice that is not tethered to a non-rigid carrier such as a wireline orslickline. However, the logging tool 50 may be constructed as a hybrid“drop tool” in that a non-rigid carrier may be used to guide or controlthe logging tool 50 until the target depth is reached. The logging tool50 may include a quick disconnect device that allows the non-rigidcarrier to be disconnected and retrieved to the surface before thelogging tool 50 is activated. A non-rigid carrier may be a wireline(power and data), an e-line (power only), or a slickline (no power ordata). The logging tool 50 may also include other devices such as ashock sub (not shown) to absorb the impact of a hard landing such aswhen the logging tool 50 is dropped into the wellbore 12.

While the present teachings been discussed in the context of a loggingwhile tripping a tool out of the wellbore, it should be understood thatembodiments of the present disclosure may be advantageously applied toother wellbore tools. Such tools may be drilling tools used to form awellbore, logging tools used to investigate a formation and/or wellbore,or well completion tools. The landing indicators according to thepresent disclosure may be used to efficiently position one or more ofsuch tools in a wellbore by appropriately positioning the travelrestrictor in the wellbore. Moreover, while the present disclosurediscusses a hydrocarbon producing well, the present teachings may alsobe used with other types of wells (e.g., geothermal wells, water wells,etc.) While the foregoing disclosure is directed to the one modeembodiments of the disclosure, various modifications will be apparent tothose skilled in the art. It is intended that all variations within thescope of the appended claims be embraced by the foregoing disclosure.

We claim:
 1. An apparatus for use in a wellbore, comprising: a toolconfigured to be conveyed into the wellbore through a drilling tubular;a landing indicator associated with the tool, the landing indicatorbeing configured to generate a pressure pulse in the drilling tubularafter contacting a travel restrictor positioned along the drillingtubular; and a sensor associated with the tool and configured toestimate at least one selected subsurface parameter while the tool is inthe drilling tubular.
 2. The apparatus of claim 1, wherein the landingindicator includes a flow dam that selectively restricts fluid flowalong a bore of the drilling tubular.
 3. The apparatus of claim 2,wherein the flow dam is a pliant member configured to collapse from aradially expanded state when subjected to a specified fluid flow.
 4. Theapparatus of claim 3, wherein the flow dam is configured to generate apressure pulse in the bore of the drilling tubular.
 5. The apparatus ofclaim 4, further comprising: a mandrel on which the flow dam isdisposed; and a sleeve configured to slide between an first position anda second position on the mandrel, wherein the sleeve at least partiallycovers the flow dam in the first position.
 6. The apparatus of claim 5,wherein the flow dam expands to the radially expanded state after thesleeve slides to the second position.
 7. The apparatus of claim 2,wherein the flow dam is configured to invert.
 8. The apparatus of claim1, wherein the landing indicator is connected to the tool to form a droptool.
 9. The apparatus of claim 1, wherein the sensor comprises at leastone of: (i) a gamma ray detector, and (ii) a neutron detector.
 10. Amethod of using a tool in a wellbore, comprising: estimating at leastone subsurface parameter using a sensor associated with the tool afterreceiving at a surface location a pressure pulse generated by a landingindicator associated with the tool, wherein the landing indicatorgenerates the pressure pulse in response to contact with a travelrestrictor in a drilling tubular.
 11. The method of claim 10, furthercomprising pumping a drilling fluid into the bore of the drillingtubular, wherein the landing indicator includes a flow dam that isresponsive to the flow of the drilling fluid.
 12. The method of claim11, wherein the flow dam responds to the flowing fluid by expanding to aradially expanded state, wherein the radial expansion causes a pressureincrease in the flowing fluid.
 13. The method of claim 12, furthercomprising pumping the drilling fluid at a flow parameter selected tocollapse the flow dam from the radially expanded state, wherein thecollapse causes a pressure decrease in the flowing fluid.
 14. The methodof claim 13, further comprising detecting at a surface location thepressure increase and the pressure decrease.
 15. The method of claim 14,wherein the landing indicator includes a mandrel on which the flow damis disposed; and a sleeve configured to slide between a first positionand a second position on the mandrel, wherein the sleeve at leastpartially covers the flow dam in the first position, and furthercomprising moving the sleeve from the first position to the secondposition after the landing indicator contacts the travel restrictor. 16.The method of claim 15, further comprising circulating fluid in thedrilling tubular while the landing indicator contacts the travelrestrictor.
 17. The method of claim 10, further comprising: tripping thetool out of the wellbore while estimating the at least one subsurfaceparameter.
 18. An apparatus for use in a wellbore, the apparatuscomprising: a tool configured to be conveyed into the wellbore; alanding indicator associated with the tool, the landing indicator beingconfigured to generate a pressure pulse in a fluid column in thewellbore after contacting a travel restrictor positioned in thewellbore.